<script>   
  class Person {   
    #age; // 定义私有属性,外部无法直接访问   
    name; // 定义公有属性   
    constructor(name, age) {   
      this.name = name;   
      this.#setAge(age);   
    }   
    // 私有函数，不能在类的外部访问   
     #setAge(age){   
       this.#age = age;   
     }   
     // 自定义方法，通过方法访问私有属性   
     getAge(){   
       return this.#age;   
     }   
   }   
   let person = new Person('张三', 20);   
   console.log(person.name); // 张三   
   console.log(person.getAge()); // 20;   
   // 报错 SyntaxError: Private field '#setAge' must be declared in an …   
   console.log(person.#setAge(18));   
   // 报错 SyntaxError: Private field '#age' must be declared in an…  
   console.log(person.#age);    
 </script> 